(USATODAY.com) - An Indiana mother has been indicted for allegedly selling her infant daughter to a man who used the girl to make child pornography.

The abuse began when the infant was 4 months old and lasted until she was 18 months old, the FBI said.

Natisha Hillard, 24, and Christopher M. Bour, 39, both of Gary, Ind., were indicted Wednesday and are being held without bail. They are to be arraigned on child pornography charges Monday in federal court in Hammond.

In the indictments, Hillard was charged with one count of sale of a child by a parent for production of child pornography and one count of permitting a child by a parent to participate in the production of child pornography.

Bour was charged with one count of purchase of a child for production of child pornography, one count of production of child pornography, and one count of possession of child pornography featuring a minor under the age of 12.

The FBI began investigating Feb. 13 after being alerted by a unnamed masseuse who said Bour had texted her about his intentions to sexually abuse the child, according to the criminal complaint.

Two of Bour's messages read:

U wanna watch me play with a baby tomorrow a real one ; )

I get a chance once in a while I was just seeing if you would hold the camera

The woman said that she had seen child porn movies on Bour's laptop during previous visits to houses he lived in while renovating them. He also said he had expressed interest in "animal love."

Later on Feb. 13, the masseuse allowed an FBI agent to assume her identity, and he then texted Bour about what he planned to do with the infant. Bour responded with graphic descriptions, said he had done it before and that the mother approved.

Yeah ive done it several times its cool she not coming just so u know u turned on by it?

Bour told investigators that the text messages were just "fantasy" or "role playing" and that he had never had sexual contact with any minor.

A week later, a Michigan City, Ind., police investigator found "numerous images depicting Bour engaged in various sexual acts with an infant female who appears to be between 6 months and 18 months old," the criminal complaint states.

Investigators then found a text from Bour to a number traced to Hillard asking for "Pic of the baby."

On Feb. 22, Bour told investigators he had met her through a dating service and knew her as "Lakita" or "Lakisha."

The court documents don't say how much Bour allegedly paid Hillard to abuse the child.